What’s the difference between a sandwich made on white bread and one made with 100% whole grain bread? Or, the difference between French fries and side salad made with spinach, tomatoes and carrots? All the foods above are carbohydrates. But the second option in both includes good carbohydrate foods (whole grains and vegetables). In the past five years the reputation of carbohydrates has swung significantly. Carbs have been touted as the feared food in fad diets. And some carbs have also been promoted as a healthful nutrient associated with lower risk of chronic disease. So which is it? Are carbs good or bad? The answer is that they are both.

What Are Carbs?

Carbsare molecules that have carbon, hydrogen and oxygen atoms.In nutrition, “carbs” refers to one of the three macronutrients. The other two are protein and fat.Dietary carbohydrates can be split into three main categories:

Sugars: Sweet, short-chain carbohydrates found in foods. Examples are glucose, fructose, galactose and sucrose.

Starches: Long chains of glucose molecules, which get broken down into glucose in the digestive system.

Fiber: Humans cannot digest fiber, although the bacteria in the digestive system can make use of some of them.

The main purpose of carbohydrates in the diet is to provide energy. Most carbs get broken down or transformed into glucose, which can be used as energy. Carbs can also be turned into fat for later use.

Good Carbs vs. Bad Carbs

Why are good carbs like fruits, vegetables, legumes, and whole grains so good for us?  Here are some of the many ways.

Good carbs are:

• Low to moderate in calorie density, which means we can eat filling amounts and satisfy our hunger, but not worry about going overboard on calories.
• High in an enormous variety of nutrients.
• Devoid of refined sugars and refined grains. In America, refined sugars like corn syrup now make up more than 20% of the calories we eat each day. That’s a big problem because our human bodies evolved over centuries and centuries to metabolize unrefined carbohydrates. Daily intakes of sugar in our bloodstream are directly linked to our current epidemics of obesity and type 2 diabetes.
• High in naturally occurring fiber, which helps lower not only blood sugar and insulin levels but also LDL bad cholesterol. Fiber-rich foods also help you fill up on fewer calories so that you can lose weight more easily. A high-fiber diet also helps prevent constipation, hemorrhoids, and certain cancers.
• Low in sodium.
• Low in saturated fat.
• Very low (often zero) cholesterol, and no trans fats.

Fake, processed (bad) carbs, the carbs consumed by most Americans, are:

• High in calorie density.Just a few bites of a corn dog or energy bar, and you’ve taken in a bunch of calories.
• High in refined sugars. Whether white sugar, corn syrup, or so-called “natural” sugars like honey and added fruit juices.
• High in refined grains like white flour.
• Low in many nutrients.
• Low in fiber.
• High (often very high) in sodium.

If you have a lot of weight to lose, or have health problems like metabolic syndrome and/or type 2 diabetes, then you are probably carbohydrate sensitive. In this case, reducing carbohydrate intake can have clear, life-saving benefits. On the other hand, if you’re just a healthy person trying to stay healthy, then there is probably no reason for you to avoid “carbs” – just stick to whole foods as much as possible. If you are naturally lean and/or highly physically active, then you may even function much better with plenty of carbs in your diet.